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Full text of "The manufacture and properties of iron and steel"

AUSTKIA-HUNGARY..                                      583
I.                                                                  II.
Crude.      Roasted.                                        Crude.      Roasted
FeO............     34.97             .....        Fe   ..............    38.03            51.80
Fe803...........     16.75            74.04        Mn..............      2.15             2.84
Mn3O4...........       2.98              4.01
Si02............       8.20            11.04
A12O3...........       2.09              2.81
CaO   ............       3.06              4.12
MgO............       2.92              3.93
CO2  .............     27.60            .....
PaOs............       0.04              0.05
SOS  .............          tr.             .....
98.61           100.00
being 500 miles away in a straight line. The transportation is expensive from both fields, owing to the heavy grades on the picturesque route through the Steiermark Alps.
Many blast furnaces of Austria are built upon a plan which is different from the usual American construction. The whole structure rests not upon solid ground, but on a pier formed of arches, so that one may walk underneath the bottom. At Donawitz the tap-hole is fifteen feet above the general level. The mere elevation is nothing unusual, as many American furnaces are built high in the air to allow the iron and slag to be carried away in cars, but in Austria it is claimed that the bottom of the furnace must be kept cool, in order to prevent the cutting away of the lining and the breaking out of the iron. This difference in construction is due very much to a difference in the work to be done. When running on ordinary Bessemer iron for the acid converter, the temperature is high, and graphite is deposited as a protective covering in the interior of the hearth; but when low-silicon iron is desired, the conditions are quite the reverse. It is safe to say that no American furnaceman will agree to make iron regularly with as low a content of silicon as the standard product at Donawitz. I have been given the following as typical:.
c.......................   4.00
Si.......................    0.10 to 0.30
S.........................       tr to 0.03
p  ........................    0.08 to 0.10
Mn......................    2.0    to 2.5
This iron is taken to a basic open-hearth furnace in a molten state, and the value of the low silicon need not be dwelt upon. The linings are of magnesite, for in Styria this mineral is as cheap